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pymodbus-dev / pymodbus

A full modbus protocol written in python
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version 1.4.0 TCP connection closed after 256 messages #276

Closed muhlbaier closed 6 years ago

muhlbaier commented 6 years ago

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Pymodbus Specific

Description

I have a client that connects to a server and reads a bunch of registers using:

Note: count is between 1 and 4 rr = client.read_input_registers(address, count, unit=1)

On the 256th transaction the connection is closed. This was not the case for the same exact code using pymodbus 1.3.x.

I added the following workaround to my code and it resumed expected functionality:

Code and Logs

MODBUS_140_WORKAROUND = True
transaction_count = 0
    for something in somethingelse:
        if MODBUS_140_WORKAROUND:
            transaction_count += 1
            if transaction_count > 200:
                client.close()
                time.sleep(0.1)
                client = ModbusClient('localhost', port=5020)
                client.connect()
                transaction_count = 0

last few log messages on the server:

DEBUG:pymodbus.server.async:send: 00fd000000050103020000 DEBUG:pymodbus.server.async:0x0 0xfe 0x0 0x0 0x0 0x6 0x1 0x3 0x2 0xd5 0x0 0x1 DEBUG:pymodbus.transaction:0x0 0xfe 0x0 0x0 0x0 0x6 0x1 0x3 0x2 0xd5 0x0 0x1 DEBUG:pymodbus.factory:Factory Request[3] DEBUG:pymodbus.datastore.context:validate[3] 726:1 DEBUG:pymodbus.datastore.context:getValues[3] 726:1 DEBUG:pymodbus.server.async:send: 00fe000000050103020000 DEBUG:pymodbus.server.async:0x0 0xff 0x0 0x0 0x0 0x6 0x1 0x3 0x2 0xd6 0x0 0x1 DEBUG:pymodbus.transaction:0x0 0xff 0x0 0x0 0x0 0x6 0x1 0x3 0x2 0xd6 0x0 0x1 DEBUG:pymodbus.factory:Factory Request[3] DEBUG:pymodbus.datastore.context:validate[3] 727:1 DEBUG:pymodbus.datastore.context:getValues[3] 727:1 DEBUG:pymodbus.server.async:send: 00ff000000050103020000 DEBUG:pymodbus.server.async:0x1 0x0 0x0 0x0 0x0 0x6 0x1 0x3 0x2 0xe1 0x0 0x2 DEBUG:pymodbus.server.async:Client Disconnected: [Failure instance: Traceback (failure with no frames): <class 'twisted.internet.error.ConnectionDone'>: Connection was closed cleanly.] DEBUG:pymodbus.server.async:Client Connected [IPv4Address(TCP, '127.0.0.1', 5020)]

dhoomakethu commented 6 years ago

This is same as #256 and #260 . A fix is available on this branch . I will try to get this in to the next release asap. Please give a try on the above mentioned branch . I will be closing this issue as of now .

muhlbaier commented 6 years ago

Sorry about that, I didn't look through the closed issues so I didn't notice #256 or #260. Thanks for the fix.